The use of tray-lid assemblies in packaging food and liquid products has been increasing in recent years due to their suitability in both conventional and microwave ovens. A tray-lid assembly includes a tray and a lid detachably connected to the tray. The tray typically includes a bottom panel, a continuous wall panel, and a continuous rim. The continuous wall panel encompasses the bottom panel and extends upwardly and often outwardly from the bottom panel. The continuous rim encompasses an upper edge of the continuous wall panel and projects laterally outwardly therefrom. The lower surface of the lid is detachably connected to the continuous rim to provide a hermetic seal which prevents water, moisture and bacteria from contacting food and liquid products within the tray-lid assembly, thereby making the products freezer-stable and shelf-stable. In the past, the seal attaching the lid to the tray has been difficult to initially open. In addition, there have been problems insuring that the food or liquid product has not been contaminated with lid fragments during the process of removing the lid. Therefore, a means for effectively opening the lid from the tray without contaminating the food or liquid is very desirable.
While various tray-lid designs have been proposed in U.S. Pat. Nos. 4,531,668, 4,871,071, 4,955,530, 4,961,464, 4,962,849, 5,090,615 and 5,234,159, the designs have failed to efficiently and effectively address the problems noted above. The designs have also failed to address problems such as creating an opening in the lid which can facilitate venting or dispersal of steam generated during microwave cooking. Therefore, there exists a need for such a tray-lid assembly which can obtain the lid removal objectives and the venting objectives.